The present invention relates in general to building structures, and, more particularly, to means for erecting insulated concrete wall panels.
Many buildings use precast concrete panels which are shipped to a building site, then erected into place. The assignee of the present invention produces such panels under the name COREWALL.RTM.. These panels include a layer of insulation sandwiched between a pair of concrete layers.
Heretofore, these panels have been moved into place using several different means. For example, lifting hooks have been cast into the front face of a panel. However, such means can only be used on panels which are not exposed, as the lifting hooks create unsightly marks on the face of the panel.
Threaded inserts have been used extensively in precast concrete panels. It is noted that COREWALL.RTM. panels are normally sawcut to length, which for all practical purposes, precludes the use of threaded inserts.
Since the aforementioned COREWALL.RTM. panels have an architectural finish on both sides, and full width insulation is required at the top of the panel, it is necessary to engage both layers of concrete when erecting the panels. This is accomplished by using two hairpin-shaped lifting hooks which are embedded in both layers of concrete. An erection bracket is then attached to these lifting hooks by two high strength "J"-bolts which are securely attached to a lifting carriage.
The bracket and carriage described above have been quite satisfactory for panels which extend above eave height. However, some buildings are designed with the top of the panel stopping just below the eaves height.
The erection bracket as described above is not suitable for use with panels stopping below eaves height, as the extended lifting plates will interfere with the final position of the panel. Using the known panel lifting device, the bolts had to be loosened, and the bracket taken off. A problem arises in the holding of the panel in position until a clevis or some other means of attachment can be made. This makes such prior lifting devices not only costly in time and effort, but creates a dangerous situation as well.
Accordingly, there is need for a means of positioning a building panel, which means will not interfere with the final position of the panel.